Probiotics and Antimicrobial Proteins最新文献

Melittin (MLT) peptide is considered due to targeting key proteins involved in apoptosis pathways to suppress tumor progression. However, the clinical application of MLT is limited due to its high cytotoxicity and poor cellular permeability. In this study, a hybrid peptide (AM1) derived from MLT and Aurein 1.2(Aur1.2) with modified properties was designed to enhance its therapeutic efficacy. A truncated form of MLT comprised of the last five C-terminal amino acids, was fused to a modified truncated Aur 1.2, in which Glycine was replaced with Tyrosine to enhance anticancer properties. Based on docking results, AM1 indicated specific interaction with the AKT1 protein in, Glu278, Asp292, and Thr308 residues. Also, it showed a specific interaction with residues Glu51, Asp86, and Asp145 in CDK2 protein. According to VMD results, the N-terminal region of the Aur1.2 peptides, excluding the first three amino acids, maintained its α-helical structure up to 50 ns. However, at 100 ns, partial structural alterations were observed, such that only amino acids 7 to 12, corresponding to the Aur region, retained their α-helical conformation. RMSD and RMSF analyses revealed no significant or undesirable fluctuations throughout the simulation of 200 ns of molecular dynamics. The RMSD values for the AM1 peptide ranged between 0.00048 and 0.64 nm and reached stability after 140 ns. Additionally, RMSD and RMSF analyses confirmed the stability of the AKT1-AM1 and CDK2-AM1 complexes. DSSP analysis indicated that the secondary structures of both complexes remained stable throughout the simulations. In addition, MM/GBSA calculations demonstrated that the binding of AM1 to both proteins is thermodynamically favorable, indicating stable and effective interactions. Furthermore, CG simulation results demonstrated the ability of the AM1 peptide to penetrate the DOPC-DOPS model membrane. In silico results suggest that AM1 is a candidate inhibitor of the PI3K/AKT and CDK2 signaling pathways, which are crucial in cancer progression; however, this finding still needs experimental validation.

This study investigates circDCAF6 in Qinchuan cattle muscle development. Firstly, circDCAF6 was screened and identified, and it was found that this circular RNA was highly expressed in muscle tissue and more stable than linear RNA. By designing interference RNA and overexpression recombinant vectors based on circDCAF6, functional studies have shown that circDCAF6 can significantly promote the proliferation of myoblasts and inhibit their apoptosis process. Through targeted regulation analysis, we found that circDCAF6 can interact with miR-181d and regulate the expression of downstream target gene CCNB1 through miR-181d, thereby affecting the proliferation and apoptosis of myoblasts. In addition, interference experiments have shown that inhibiting CCNB1 can significantly reduce the proportion of cells in the S phase of the cell cycle and increase the proportion of early apoptotic cells. This effect can be partially rescued by co-transfection with circDCAF6. In summary, this study suggests that circDCAF6 plays a critical role in the proliferation and apoptosis of Qinchuan cattle myoblasts by targeting miR-181d to regulate the expression of CCNB1. These findings provide a new perspective for a deeper understanding of the molecular mechanisms underlying muscle development and may offer new molecular targets for genetic improvement in beef cattle.

Fluoxetine has been increasingly recognized for its antimicrobial properties and potential to alter gut microbial composition and function. This study aimed to investigate the effects of fluoxetine exposure on Escherichia coli ATCC 25922, focusing on growth curve, protein secretion, metabolite-associated cytotoxicity, antibiotic interaction, and drug depletion. To assess potential impacts on bacterial physiology, E. coli was exposed to fluoxetine for 72 h. Bacterial growth and protein levels were measured. Supernatants were tested for cytotoxic effects on SW480 and HMC3 cell lines using MTT assay. Colistin susceptibility of Pseudomonas aeruginosa was evaluated in the presence of these supernatants to investigate the indirect modulation of antibiotic susceptibility. Fluoxetine exposure reduced bacterial growth while increasing extracellular protein levels. MIC values for colistin increased over time in both groups but showed no fluoxetine-specific differences. Although cytotoxicity testing specifically found reduced cell viability in fluoxetine-treated culture supernatants, no statistically significant difference was found compared to untreated controls. Finally, HPLC analysis demonstrated complete fluoxetine depletion from the bacterial culture by 72 h. These findings highlight potential microbiota-drug-host interactions and emphasize the need for mechanistic investigation of fluoxetine's effects on microbial physiology and host cell health.

Enterocin LD3, a bacteriocin produced by Enterococcus hirae LD3, was previously isolated from batter of Dosa and characterized for unique mass, sequence, stability and antimicrobial activity against pathogenic bacteria. In this study, safety assessment of enterocin LD3 was evaluated in cell lines and mice model. It does not show haemolysis up to 400 µg/mL and IC₅₀ was found to be 643.16 ± 6.75 µg/mL against human embryonic kidney (HEK-293) cell line. Enterocin LD3 was purified to homogeneity and applied intraperitoneally to male Swiss albino mice. The level of SGOT (149.5 ± 2.0 U/L), SGPT (68.7 ± 9.8 U/L), urea (25 ± 4.2 mg/dL) and creatinine (0.92 ± 0.1 mg/dL) were found to be in the normal range. In contrast, acetamiprid-treated mice (positive control) exhibited significantly higher level of SGOT (288.4 ± 38 U/L), SGPT (98.3 ± 31.1 U/L), urea (32.8 ± 4.7 mg/dL) and creatinine (2.4 ± 0.7 mg/dL). In addition, there were no significant changes observed during histopathological analysis of liver and kidney tissues after treatment of mice with enterocin LD3. Although, these are initial findings and need further investigations, it indicates safety profile of enterocin LD3 for its applications in food and clinical settings.

The intensifying challenge of antimicrobial resistance (AMR) has outpaced traditional antibiotic discovery, leading the World Health Organization to call for the rapid exploration of alternative therapeutic options. Endolysins-phage-encoded peptidoglycan hydrolases-exhibit potent bacteriolytic activity against multidrug-resistant pathogens and show minimal propensity for resistance development. However, their clinical translation remains hindered by several critical barriers, including resource-intensive discovery processes, limited permeability through the outer membrane of Gram-negative bacteria, and various chemical, physical, and immunological challenges. In this review, we systematically summarize the fundamental characteristics of endolysins and integrate a tripartite strategy to enhance their therapeutic potential: bioinformatics-based pre-screening mining stage, mid-stage optimization stage of engineered modifications and post-enhancement stage combining encapsulation and formulation. Challenges inherent to each stage are critically analyzed, and future directions for endolysin development are discussed. Such multiple strategies provide a comprehensive roadmap for overcoming current barriers and accelerating the development of next-generation endolysin-based therapies against AMR.

The gut microbiome is crucial for human health, and its imbalance, known as dysbiosis, is associated with diseases such as inflammatory bowel disease, metabolic disorders, and neurological disorders. Traditional treatments, such as probiotics and fecal microbiota transplants, often lack precision, making the emerging field of nanomedicine a promising alternative. This review introduces the "MOF-Microbiome Axis," which explores the interactions between metal-organic frameworks (MOFs), versatile, porous materials, and the gut microbiome. It focuses on designing gastrointestinal-targeted MOFs that are biocompatible and responsive to stimuli. We discuss how MOFs can serve as scaffolds, controlled-release vehicles, and metabolite scavengers, highlighting their therapeutic applications in targeted antimicrobial therapy, enhanced probiotic delivery, and immunomodulation. The review also addresses important challenges in biosafety, scalable production, and personalized treatment, suggesting future directions such as bio-hybrid systems and precision microbiome editing. Overall, the MOF-Microbiome Axis offers a new perspective on microbiome engineering and advanced therapeutic approaches.

Diarrhea, a common gastrointestinal disorder, is often exacerbated by conventional antibiotic treatments that disrupt gut microbiota, necessitating the exploration of Lactic acid bacteria (LAB) alternatives. This study investigates the therapeutic potential and mechanisms of Streptococcus thermophilus NCU074001 (ST) in a rat model of PEG3350-induced osmotic diarrhea. ST treatment mitigated diarrheal symptoms and improved key markers of intestinal health by acting as a key modulator of the gut ecosystem. Its efficacy was driven by balancing immune responses via elevated IL-10 and suppressed pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, IFN-γ). Furthermore, ST reinforced the intestinal barrier by upregulating MUC2 expression and reshaping gut microbial ecology by suppressing certain genera (Bacteroides and Anaerofilum) while enriching others (Lactobacillus, Akkermansia, Phascolarctobacterium, and Parabacteroides). This taxonomic restoration was accompanied by a functional metabolic shift, characterized by increased production of short-chain fatty acids (acetate and butyrate) and a targeted modulation of tryptophan metabolism that enhanced the production of anti-inflammatory indole derivatives. Correlation analyses suggested potential links between ST-mediated microbiota remodeling and barrier strengthening and immunomodulation. Collectively, these results indicate that ST functions as a promising probiotic integrating immunomodulation, microbiota restoration, and metabolic reprogramming to alleviate diarrhea, and thus presents a promising therapeutic alternative to conventional antibiotics.

Aquaculture faces increasing challenges related to disease management and the need for sustainable alternatives to antibiotics that ensure productivity, fish welfare, and environmental sustainability. Probiotic bacteria, particularly lactic acid bacteria (LAB), have emerged as promising candidates for improving fish health through intestinal colonization, competitive exclusion of pathogens, and production of bioactive compounds. This study reports the phenotypic and genomic characterization of four Pediococcus pentosaceus strains (BE2, BE6, BE8, and BE9) isolated from the intestinal microbiota of freshwater fish (Cichlasoma spp.). Safety assessments revealed no hemolytic activity, coagulase production, or gelatinase activity, and antibiotic susceptibility profiles were consistent with international guidelines for probiotic candidates. The isolates demonstrated in vitro tolerance to acidic pH and bile salts, with viable counts decreasing by less than 2 log units under simulated gastrointestinal conditions. Adhesion assays using human Caco-2 cells showed approximately 30% adhesion efficiency. All strains exhibited growth on prebiotic substrates, including mannan oligosaccharides (MOS), fructo-oligosaccharides (FOS), and inulin (INU), with strain-specific preferences. Genomic analyses confirmed species-level identity and revealed biosynthetic gene clusters associated with the production of vitamins such as riboflavin, bacteriocins including penocin A and pediocin PA-1, alongside intrinsic resistance and stress response genes. Cell-free supernatants inhibited key aquaculture pathogens (Streptococcus agalactiae, Aeromonas hydrophila, and Francisella orientalis) in agar diffusion assays, suggesting antimicrobial potential mediated by bacteriocins identified in your genome. Therefore, the isolated strains exhibit promising functional and genomic characteristics, supporting their potential use as probiotics and components of synbiotic consortia for aquaculture applications.

The emergence of antibiotic-resistant pathogens has raised growing concern in aquaculture, prompting the development of probiotic-based strategies for disease control. In this study, a novel strain of Lactococcus lactis (LZK-02) was isolated from the intestine of healthy largemouth bass (Micropterus salmoides) and evaluated for its probiotic properties and immunomodulatory potential. The strain was identified through polyphasic taxonomy, including morphological characterization, 16 S rRNA gene sequencing, and whole-genome analysis. In vitro assays showed that LZK-02 exhibited strong antagonistic activity against Staphylococcus aureus, along with acid and bile tolerance, auto-aggregation, surface hydrophobicity, and digestive enzyme production. Genome annotation revealed genes related to stress resistance, adhesion, and bacteriocin biosynthesis. A feeding trial was conducted using diets supplemented with 10⁷-10⁹ CFU/g of LZK-02 for eight weeks. Results showed significant improvements in growth performance, intestinal histomorphology, antioxidant enzyme activities (SOD, CAT), and immune parameters (ACP, AKP, lysozyme) in treated groups compared to the control. Following intraperitoneal challenge with S. aureus, LZK-02-fed fish exhibited higher survival rates and lower bacterial loads in the liver. These findings suggest that L. lactis LZK-02 is a safe and effective probiotic candidate capable of enhancing immune responses and disease resistance in largemouth bass, and may serve as a potential alternative to antibiotics in intensive aquaculture.

Obesity is a global health challenge, but current pharmacological interventions (e.g., orlistat) often cause adverse effects. Although probiotics show potential in alleviating obesity, the mechanisms by which microencapsulated compound probiotics exert anti-obesity effects via peroxisome proliferator-activated receptors (PPARs) remain unclear. Our previous study demonstrated that pectin beads encapsulating compound probiotics (Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Bifidobacterium breve) exhibited superior anti-obesity effects to single strain in high-fat diet (HFD)-fed rats. Here, we systematically investigated the alleviating effects of these microencapsulated compound probiotics (1 × 10⁸ CFU/day, oral gavage) against HFD-induced obesity in C57BL/6J mice (8-wk intervention) via PPARs-mediated regulatory mechanisms, with orlistat (24 mg·kg^- 1·day^- 1, oral gavage) as the positive control. Results showed that the microencapsulated compound probiotics significantly reduced weight gain rate (35.68% vs. 58.51% in HFD group, P < 0.05) without affecting food intake, improved hepatic steatosis (reduced hepatocyte vacuolation), and maintained glucose homeostasis (oral glucose tolerance test AUC: 14205 vs. 2150 mg·min/dL in HFD group, P < 0.05). Compared to HFD controls, the probiotics significantly reduced serum total cholesterol (2.90 vs. 6.31 mM, P < 0.05) and interleukin-6 (IL-6: 10.04 vs. 17.66 pg/mL, P < 0.05). Mechanistically, the probiotics downregulated PPAR-γ (0.65-fold vs. HFD, P < 0.05) to inhibit adipogenesis. 16 S rRNA sequencing revealed that the probiotics preserved gut microbial diversity (Shannon index: 5.2 vs. 4.1 in HFD group, P < 0.05), whereas orlistat caused gut dysbiosis (Shannon index: 3.8, P < 0.05 vs. ND group). Together, these findings clarified that microencapsulated compound probiotics alleviate obesity via PPAR-mediated lipid metabolism regulation, while protecting gut ecology-offering a safe and effective microecological strategy for obesity prevention.